monogamy

Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

n. The practice or condition of having a single sexual partner during a period of time.

n. The practice or condition of being married to only one person at a time.

n. The practice of marrying only once in a lifetime.

n. Zoology The condition of having only one mate during a breeding season or during the breeding life of a pair.

from Wiktionary, Creative Commons Attribution/Share-Alike License

n. A form of sexual bonding involving a permanent pair bond between two beings.

from the GNU version of the Collaborative International Dictionary of English

n. Single marriage; marriage with but one person, husband or wife, at the same time; -- opposed to polygamy. Also, one marriage only during life; -- opposed to deuterogamy.

n. State of being paired with a single mate.

from The Century Dictionary and Cyclopedia

n. The practice of marrying only once, or the principle which upholds that practice; the principle that forbids remarriage after the death of a former husband or wife: opposed to digamy. See bigamy, 2.

n. The condition of being married to only one person at one time: opposed to bigamy or polygamy. See bigamy, 1.

n. In zoology, the habit of having only one mate; the habit of living in pairs; the paired state.

Now, though it be true that Nature's ideal is that which we call monogamy, it may be perfectly true that we have not yet reached that level of morality which makes that condition universally practicable.